This invention relates to logic systems and more particularly, it concerns an electro-mechanical logic system for photographic film strip viewing apparatus operable automatically to process, project and rewind a film strip connected between supply and take-up spools contained in a multi-purpose cassette.
U.S. Pat. No. 3,830,564 issued Aug. 20, 1974 to John F. Batter, Jr., U.S. Pat. No. 3,909,120 issued Sept. 30, 1975 to Joseph A. Stella and U.S. Pat. No. 3,941,465 issued Mar. 2, 1976 to Irwin E. Figge, et al are representative of a larger number of prior art disclosures directed to a motion picture system in which a cassette contained film strip may be exposed, processed and viewed by projection of successive image frames formed on the film strip without removal from the cassette, principally as a result of a one use processing facility provided in the cassette. The system represented by this prior art has evolved to a point where one desiring to take and view motion pictures need merely place the cassette in an appropriately designed motion picture camera, expose the film strip in traditional fashion, remove the cassette from the camera and place it in a viewer apparatus, operable upon rewinding the film strip to apply cassette contained processing fluid to the strip, and within minutes of time, view the motion pictures he has taken by projection of light through the processed film strip.
Because the exterior appearance of the cassette remains unchanged whether processed or unprocessed and also because the same cassette will be re-used to view the processed film strip after it has once been processed, the viewing apparatus is appropriately automated to discern the condition of the film strip in the cassette and to program respective process, project or rewind operational modes in accordance with the information provided by the condition of the film strip in the cassette. Also because the viewer represents a basic piece of equipment constituting a major portion of the system from a cost standpoint, it must be capable of operation as effective for repeated viewing and rewinding of the processed film strip as it is for processing the film strip in the first instance.
Although the present state of the art relating to viewer/processors for such cinematographic systems has demonstrated functional viability, there is need for improvement of such equipment by which functional reliability of existing systems may be retained or improved but with lower manufacturing costs from the standpoint of both individual component manufacture and component assembly. The capability for film processing is perhaps among the more impressive characteristics of the viewer in such systems. This capability, however, has in the past required very complex viewer control logic which has detracted somewhat from otherwise effective operation of the viewer as a projection apparatus during which processed film is conventionally projected and rewound in accordance with well-known motion picture viewing operations.